Beat the soft butter and sugar together until light and fluffy, about 3 minutes
Beat in the egg and vanilla until well combined, scrape down the sides of the bowl and continue beating for 1 minute
Mix flour, baking powder and salt together and add them to the butter/egg mixture
Shape into a log about 1 and 1/2 inches in diameter and wrap in plastic wrap for at least 30 minutes or up to 5 days
When ready to bake heat your oven to 375 degrees
Slice into 1/4 inch to 1/2 inch slices depending on how large you want the cookies, and place 1 inch apart on a parchment lined baking sheet
Bake for 8-10 minutes until the cookies are lightly browned